Building off some of the points
@DomainVP made..
Regarding indexing a new site, it can take hours to days. As long as their are no prior penalties, you can get any site indexed equally as fast. Set up a sitemap, add it to webmaster tools, add your domain to social media accounts, and you should have no problem. Essentially, the best way to get your site indexed is to put your url out there as much as possible so that you increase your chances of being crawled by Google's robots.
Indexing your website doesn't really mean squat though for ranking. Sure you can get your website on the first page quicker for a longtail EMD like "TheBestLittleBookstore", but it's going to take authority, quality content, and time for an EMD like "BestBookstore".
It's extremely important to understand the significance SEO plays in domaining if you want to be successful.
I've been buying domains and doing SEO for myself for years, own an SEO agency where I've done SEO for a variety of different types of local/small businesses, and also invest in domains to resell, so I'll try to add as much insight as I can from an enduser/domainer perspective.
1. No matter what anyone says, EMDs are better for an enduser. Especially with geo domains. With every client I have ever had, if the EMD is in use for their keyword, it's in the 7-pack. If optimized well, it's #1 in the 7-pack, and if it's optimized well and has built up age/authority, it's #1 in the 7-pack and organic rankings.
BUT as a domainer there are only certain instances that an EMD is worth investing in - and most of the good ones have long been taken. To put it simply, the CPC + Search Volume + Competition should all be taken into account. The CPC + Search Volume gives you an idea of if the name is valuable enough for an enduser to justify buying the domain at a premium. The competition tells you if the enduser will benefit from having the EMD vs. some other variation. Specifically, you should be looking at the DA, PA, and domain name of those already ranking for your keyword. (I use MozBar and SEOQuake toolbar to get all of this info instantly)
BUT as an enduser/SEO, there are very few instances that I would ever buy an EMD in .com. As much as I believe in ".COM is King" as a domainer, it's not so much the case as an SEO. The .com, .org, .net are equal to me, and "-" alternatives aren't far behind. If I can get my hands on any of these and the .com is undeveloped sitting in a domainers portfolio, I will be able to outrank the .com no problem once someone else tries to develop it. Of course, you sacrifice the mental .com is more "trusted" aspect, but for the difference in price, I could care less.
2. For e-commerce, web based businesses, and blogs there are very different criteria for registering domains. Contrary to what people like to spout, hand regging domains to resell to endusers in this market is far from dead. If an enduser is naming an online business, they're more than likely going to choose a "brandable" domain name. And to be clear, a "brandable" to me is anything that is not an EMD - namely keyword+word.
So when I hand register a domain to resell, I look at past sales to find a popular keyword, and then attach it to all of the most popular suffixes. (I made a tool to simplify this, but believe me there are tons of good domains available out there.)
Here's an example of what I mean from a few days ago:
I saw that MerchantCard sold for $2,000, so I checked out other sales using the word merchant. I found that in the last year MerchantGuard sold for $3,000, MerchantSquare sold for $4,000, and MerchantConnection sold for $3,000.
So I used my tool to find what "merchant" domains were available and tried to find similar domains to ones that have sold in the past. One of the available domains was MerchantCube/com. It fit the criteria I was looking for, keyword+cube names have sold very well in the past, so I regged it for a whopping $1.99.
3. Then you have the endusers/seos like myself. We make up a HUGE percentage of drop-catchers and are the reason most domains get driven up so high in aftermarket auctions. When we build online businesses or blogs, the name is nowhere near as important as what's behind it.
I won't go into specifics as I'm already rambling, but what I mean by this is the backlink profile, DA, PA, and drop history. If everything passes, and the name isn't completely off-the-wall, I will use it as the name of my next project. You're essentially getting YEARS of work done by someone else, which plays a massive role in ability to rank.
The profits that can be made by rebuilding and monetizing these domains is far greater than what you may be able to get from reselling them. And then you can either flip the website for more profit, or use it to build the most powerful seo tool of all, a PBN.
When building a PBN you would need to follow what VP mentioned earlier about having separate hosting packages for more than 1 website. PBNs are complex and would take hours to describe, but they fuel the competition and high prices in the drop catching arena.
This is also something important to consider when using sites like namebio.com to value domain names. Most of the sales listed are dropped domains that have high price tags because of their profile, NOT the quality of the name itself.
Additionally, you should always do some research on any domain that you decide to purchase from the "deleted" section of expireddomains.net. There is always a good chance that no one caught it because it has been penalized or has a spammy profile, which can really hurt the resell value of the domain.
4. Going back to having more than 1 domain for a website/business, there are a few things to consider. Most importantly, I would advise to AVOID having more than 1 website for the same business. What you can do, however, is use additional domains as a "vanity" url like you mentioned in the OP.
So say a company has a business with an established website, they can redirect a pronouncable/easy to remember url to their website to put on business cards, fliers, ads, etc. By doing this, you can rank an EMD in the .org, .net, with dashes, etc that generates leads and new customers in the search engines, but have another that is used only offline. (ie, Houston-Carpet-Cleaning.com online, SmithCompany.com offline)
Another common online marketing practice is using keyword domains for landing pages that do not have any connection to your primary site. This is the bread and butter for lead-gen businesses. My agency does PPC (adwords) for most of our clients, and I use this method every single time. This is also why you often find long tail domains registered when there is a much cleaner alternative unregistered. So don't be surprised if you buy it and the owner of similar domains has no interest..
The way that this works is you register a keyword rich domain or attention getting domain and use it strictly for lead generation in a PPC campaign. The adwords algorithm is much different than the google algorithm, and domain name criteria is much different as well. In order to get your ad to the top of google's ads, they use a site relevance ranking that assesses how well it fits the search term that was entered. Go type in a competitive term and you'll notice that all of the websites in the ads are exactly the same. Single page, basic layout, stuffed with keywords, and a HUGE opt-in form.
A quick random example of this, I typed in "Title Loan". The domains that appear on top of the ads are findatitleloans.com, overnighttitleloan.com, and 15minutetitleloan.com. Each have nearly identical layouts, are not the names of actual businesses, and belong to a much larger entity. A quick whoisology check of 15minutetitleloan.com shows you the owner is Quick Cash, and they also own 113 other domains that are all some variation of title loans. So while you may be able to flip domains like this to lead gen sites if you can actually get a hold of someone with authority, you will almost never be able to resell them for a decent markup.
I could add much more, but I think I'll go ahead and stop there haha. Hope some of this info was able to help some of you guys!